Abstract
We characterized the voltage-activated Ca2+ channels involved in noradrenaline (NA) release from gastric sympathetic neurons using isolated, vascularly perfused rat stomach. The evoked NA release by electrical stimulation of periarterial nerves was abolished by calcium removal from the perfusion medium and by cadmium. ω-Conotoxin GVIA (N-type Ca2+-channel blocker) effectively and ω-conotoxin MVIIC (N/P/Q-type blocker) slightly inhibited the evoked NA, while ω-agatoxin IVA (P-type blocker) had no effect. These results suggest that ω-conotoxin GVIA and ω-conotoxin MVIIC-sensitive N-type Ca2+ channels are involved in NA release from the rat gastric sympathetic nerve terminals.
